Breton is a Brythonic language belonging to the branch of Celtic spoken over most of Britain from prehistoric times until the Saxon invasions. It is closely related to Cornish (Cornwall:Kernow) and Welsh (Wales:Cymru) and more distantly to the other surviving Celtic languages, Irish, Scottish Gaelic and Manx Gaelic (Ireland, Scotland, Isle of Man) (The Goidelic group).

It is difficult to tell precisely when the Breton language was born. As early as the sixth century the new country was established and known as "Lesser Britain", but for many centuries its language remained close to the one of Great Britain - very close even to the dialect spoken in the South West. The eighth century is the milestone where Breton, Cornish and Welsh are considered as different languages.

The Breton language remained spoken by the heads of the Breton state until the twelfth century when they abandoned it. Little by little, it became the language of the west-end of Brittany and of the low class of the society as noble and "bourgeois" people left it in favor of the French language.

Progressively, its usage was restricted to the part of Brittany which is now called Breizh-Izel (Low Brittany) (to the west of a line running from Plouha in the north down to the Rhuys Peninsula in the south).

It was then decided to start teaching the French language to all people in France in order to get rid of all other pre-existing languages - dubbed scornfully patois. This was very successful in Brittany, thanks to a method designed to shame children speaking breton at school (state or catholic). This action to kill the Breton language continued until the year 1960 when the schools no more received children speaking only Breton.

Today, as the French linguistic position is still to only put forward the french language considered as the language of the Republic, the Breton language remains spoken by circa 300,000 persons (to be compared with the 1,300,000 persons in 1930). This number will probably drop under 100,000 because the largest part of its speakers are of an older generation.

The Breton language is the only Celtic language without official recognition.